Furnace for heat treating metals



Oct. 18, 1932. w. R. CHAPIN FURNACE FOR HEAT TREATING METALS Filed Nov. 13, 1929 2 Sheets-Sheet 3mm WiUiamRQhapin Oct. 18, 1932. W.,R.CHAPIN ,5

FURNACE FOR HEM T TREATING METALS Filed Nov. 15, 1929 2 Sheets-Sheet 2 gwomto p William ROhapin Patented Get. 18, 1932 PATENT OFFICE WILLIAM R. CHAPIN, OF INDIANAPOLIS, INDIANA I FURNACE r03 HEAT renaming METALS Application filed November 13, .1929. s mi No. 406,942.

This invention relates to heat treating furnaces, and particularly to furnaces usedin the art of heat treating metal.

An object of the invention is to provide 5' a furnace in which work" may be treated so as to give it a more even temper than was possible with furnacesheretofore, and to enable an operator to do work much faster than could be done with furnaces heretofore known. 7

Referring to the accompanying drawings, which are made a part hereof and on which similar reference characters indicatesimilar parts, i v

Figure 1 is a perspective view of my furnace,

unit of the furnace, with a portion shown in sectlon, I

Figure 8 is a plan View of one unit of the furnace with a part shownas a horizontal Figure 5 shows a side View of a group of circular objects as suspended in the heat treating chamber, and

Figure 6 shows an end view of the suspended work shown in Figure 5.

In furnaces heretofore in use for heat treating metal in the hardening process it has been customary to place the material to be treated upon the floor in a heating chamber or upon supports within the chamber. When placed upon the floor the material was not uniformly heated, since the surface of the material which came in contact with the floor of the furnace was not exposed tothesame temperature as the other surfaces; likewise when the material was supported upon fixed supports within the furnace the parts which contacted with the supports did not receive the same even temperature as the exposed parts,

with the result that these parts would not be heated exactly like the remaining parts. This sometimes causes the metal to warp out of shape. To overcome the objections to furnaces of this sort, I provide for suspending the parts to be tempered within the furnace.

: In this way all surface areas are subjected Figure 2 is an end view in elevation of one s to the sametemperatures, witlithe result that the metal is given uniform temper throughout. suspending the objects within the chamber moreoverresults in less destructive Wear upon the floor of the furnace. More over, by suspending the material I am able 3 M to heat treat a much greater amountin each chamber than waspossible when the material was placed upon the floor or laid upon supports within the chamber.

11 heat treating steel it is desirable to main- 5 tain the heating chamber at as nearly a uniform temperature as possible. Withthe old furnaces it was customary to put the material to be treated within the furnace and allow it to remain there until it was sufficiently heated. When the cold material was first put into the furnace it necessarily reduced the temperature so that the temperature in the furnace would be considerably lower as each new defect with furnaces, I providea number of units of different temperatures. The material is placed in the unit of lowest temperature, and then moved to a unit of higher" temperature,from which it is'placed in the final high temperature furnace chamber. The material thereforeis preheated almost tothe desired temperature'before it is'placed in the final heating chamber. When placed in the last chamber therefore it does not considerably reduce the temperaturepwithin the chamber.

In the drawings, numerals '10, 11 and12 indicate units comprising my furnace, in

which 10 indicates a low temperature unit, 11

an intermediate, and 12 a high temperature unit.

means of rods 13 and suitable corner post-s14, here shown as made of angle iron and having suitable ears thereon for receiving the endof the rods 13. Units 10, 11' and 12 areidentical in construction. The high temperature unit 12'theref0realone will be described in detail material, such. for example as cork brick. .7

These units are built up from suitable material assembled and secured'together by batch'of work was put in. To overcome this chamber being furtner tal floors 24 which as shown in Fig.2 d1v1-de side of the work chamber.

chambers on the different levels.

have more than two preheating units.

The bottom of the furnace consists of layers of suitable fire resisting material, the outer layers 17 and 18 preferably being made of common red brick and the inner walls 19 and 20 of suitable fire brick. The inner walls. 21 are likewise built up of suitable fire brick. A work chamber 22 within the furnace is formed by surrounding walls 23 of suitable material, such for example as thin or split fire brick. A number of firing chambers 25 surrounding the working chamber are provided between the walls 23 and the wall 21, these 1 formed by horizonthe heating chambers into four units on each I These heating chambers or combustion chambers 25 have ports 26 on each side of the unit into which ports suitable combustion nozzles, not shown, project for heating the chambers. The heating chambers on each side of the work chamber preferably extend across the furnace and around one end of the work chamber where they enter a flue 30 which connects the firing As shown there are four burner chambers on each side of each unit of the furnace,these four chambers entering into the flue 30 at one end and the chambers on the other side of the unit entering the flue 31 at the other end. The walls 23 on the inner sides of the combustion .chambers being relatively thin conduct the heat from the heating chambers to the work chamber, in which the work'27 is suspended by any suitable supporting means 28. The work is placed in and taken from the work chambers through openings 29 in the top of the furnace. These openings are closed by any suitable doors.

In Figures 5 and 6 are shown a number of circular pieces of work 32 suspended on hooks 3.8 which are supported on a bar 34 v which may be placed longitudinally of the chamber 22 instead of across it as the rods .28'are placed. This is a convenient means of suspending circular saws.

While I have shown my furnace as composed of three units, consisting of a final high temperature unit and two preheating units, it should be apparent that I do not limit myself to a furnace of three units, as it might be desirable under certain circumstances to viously, moreover, I do not limit myself to the firing chambers which surround the work chamber, nor 1s the particular material out of which the furnace is constructed meant to .hmit'the invention to the use of such material.

It will be obvious to those skilled in the device without departing from the spirit of the invention, and I, therefore,-do not limit myself to what is shown in the drawings and bers and separated therefrom by imperforate walls, the combustion chambers having alternate fuel inlets from each side extending along one side and one end of a work chamber andpassing out through the top of the furnace, the work chamber having a cover with an elongated slot through which the work to be heat treated may be suspended, substantially as set forth.

2. A heat treating furnace comprising a plurality of combustion chambers arranged one above the other and having fuel inlets thereto and fine outlets therefrom, a work chamber completely surrounded by the combustion chambers and separated from the combustion chambers by imperforate walls,

a cover plate for the work chamber having a relatively long narrow slot therein, means positioned in the slot for supporting work, said pieces of work being supported so as to be out of contact one with the other whereby the work may be evenly heated throughout, substantially as set forth.

In witness whereof, I have hereunto set my hand at Indianapolis, Indiana, this 18th day of October, A. D. nineteen hundred and twenty-nine.

WILLIAM R. CHAPIN.

particular number and arrangement of the art that various changes may be made in my 7 

